When a woman we'll call "Caroline" looked at her 11-year-old daughter's phone and saw a man with a beard had friended her, Caroline got mad.

When he asked for a nude picture of her little girl, Caroline decided to get even.

She was looking at a Target store circular and noticed a picture of a young woman wearing nothing but a bra.

"So I just grabbed my cell phone, took a picture of it, and sent it to him," she said.

The ploy worked. The 23-year-old suspect sent dirty pictures and messages back, she says, just the evidence police in Florida needed to charge him with preying on a child.

Caroline says she came forward because she's worried about what would've happened if she hadn't been paying attention to what her daughter was doing on social media. She hopes other parents will now keep a closer watch